DE2328016A1 - METHOD FOR PURIFYING DAIRY WASTE - Google Patents

Description

Dr. Werner Haßler ¹ Lüdenscheid, 'May 30, 1973 - B.'

PATENT ADVERTISER _A 7334

588 LODENSCHEID
Asenberg 36 PO Box 1704

Applicant: Agence Nationale de Valorisation de la Recherche (ANVAR) 13, rue Madeleine Michelis 92200 Neuilly sur Seine / France

Process for cleaning up dairy waste water

The invention relates to a method for the microbiological cleaning of dairy waste water.

Dairy wastewater consists mainly of whey, which '' Liquid milk phase that is obtained after the casein has been precipitated (by adding rennet or acid) for cheese production.

Whey serum has an average composition of:

Water 93.5%

Lactose. 4.5%

Nitrogen compounds "0.9%

Fats 0.3%

Minerals 0.6%

Lactic acid 0.2%

One of the main components of nitrogen compounds is a protein, namely lactalbumin.

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The in itself obvious discharge of this dairy waste water to the receiving water is usually not allowed because it is a Changes the chemical and microbiological composition of the receiving water and promotes the development of microorganisms. which release acidic or toxic products, which in turn lead to unacceptable ecological disturbances System (fish death and flora modification) lead.

One method that allows the whey to be disposed of is to remove it immediately or after concentrating or removing it. Use drying for cattle feeding. The direct exploitation the whey requires the assignment of a cattle breeding business (pig fattening) close to the dairy. The concentration or drying of the whey on the other hand is only profitable if the amount of whey to be treated is about 1,000,000 liters. Most dairies, however, do not produce such large quantities of whey (in a medium-sized dairy 30,000 liters per day), as if the operation of treatment plants would be economical, and they can fail for various reasons do not join pig fattening either.

Another method is to use the whey as a fertilizer.

Most often, however, the direct transfer is still the most economical Solution, albeit the most dangerous one for the environment.

A previous cleaning is therefore very desirable, in particular a microbiological cleaning that is carried out on appears most suitable to take into account the nature of the whey.

The microbiological purification of dairy wastewater has always encountered two problems that are still unprofitable today.

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could be solved economically. The first problem arises from the very high concentration of lactose in the whey.

It is well known that nutrient media can no longer be sufficiently aerated to allow the bacteria to multiply quickly, if their concentration exceeds 3 g dry weight per liter. On the other hand, with a lactose concentration of 45 g per liter theoretically achieve at least a dry weight of 10 g / l bacterial substance The need to dilute the whey, in turn, leads to a simultaneous increase in the dimensions and the cost price the cleaning system.

The second problem relates to the development of microorganisms that require the addition of often substantial amounts of organic Compounds or minerals, such as nitrates, are required in the whey, which further adds to the cost of cleaning elevated. Because of this, hitherto have economic considerations microbiological cleaning of whey is excluded

It has now been found that certain strains of bacteria on undiluted whey without the addition of organic compounds or Minerals develop and sometimes eliminate more than 80% of the dry whey matter by the bacteria is consumed or reduced to C0_ and H ~ 0. The one in that Bacteria used in cleaning processes according to the invention are aerobic, non-pathogenic strains that contain at least one proteolytic enzyme and a ß-galactosidase or lactose oxidase own. In particular, give proteolytic strains the genus Enterobacter and the genus Serratia from the Enterobacteriacae family excellent results: This is the case with the Enterobjacter liquefaciens ECL strains and 67 I, Serratia atypical 3470 (the strains mentioned are contained in the collection of the Pasteur Institute, where the strains BCL and 67 I are deposited under the numbers 1003 and 1002.) "

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These tribes are particularly interesting because they make you sufficiently have a rapid metabolism so that the process can be carried out in a reasonable time because they do not have any for the Fauna of the receiving water produce toxic compounds and because they are sufficiently adapted to the "reproduction in whey" to avoid contamination by other potentially toxic types of bacteria.

The aerobic character of these bacteria also makes it unnecessary to acidify the whey too much.

The method according to the invention is therefore characterized in that that one .'The wastewater with the help of at least one proteolytic, aerobic, non-pathogenic bacterial strain containing at least one ß-galactodidase or one lactose oxidase owns, subjected to fermentation at a temperature between about 20 and 37 C and then the bacterial mass from the fermentation solution separates.

Further characteristics and features of the invention emerge from the following description and the subclaims.

The whey can be cleaned in fermentation devices known per se such as bowls, fermenters or the like. be performed. One takes a vigorous inoculation of the whey with the bacteria ensure good ventilation and keep the temperature between 20 and 37 ° C for 48 hours, preferably at 30 ° C. In In certain cases it is necessary to control the pH and, if necessary, to increase it by adding a base a value between 6 and 7 in order to preserve the activity of the bacteria.

Under these conditions one obtains after centrifugation for the purpose of separating the bacterial masses, a drain with a very low dry matter content, often less than 20% of the Initial value.

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The separated, protein-rich bacterial mass can be used as fodder can be recycled, whereby the costs of cleaning can be further reduced. ■

A portion of the culture (approximately 10%) should be saved as inoculum for the following purification cycle.

For a medium-sized dairy it is necessary to have a fermentation tank of about 60 m capacity, which corresponds to storage of the whey accumulating in 48 hours and is not a very essential investment.

The invention is explained in more detail below with the aid of examples.

Example 1 ,

Purification using the BCL Enterobacter liguefaciens strain

The culture medium consisted of a sterile whey, which on was obtained in the following way:

Pasteurized commercial milk (LACTEL) at 37 ° C was used mixed with 3 ml / 1. technical rennet, kept at 37 ° C for 1 hour and then filtered through hydrophilic cheesecloth. The filtrate was centrifuged at 9000 rpm for 15 minutes. The protruding Liquid was sucked off in the presence of "Hyflo supercell". For sterilization, it was filtered through a nitrocellulose filter (Millipore).

The bacterial concentration of the cultures was determined by measuring the optical density at 600 nm after the Relationship between optical density and dry matter had been determined experimentally.

The content of the whey and the bacterial filtrates was measured by placing 5 ml of liquid in a platinum » were dried to constant weight.

placing 5 ml of liquid in a platinum dish at 120 ° C up to

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The reducing sugar content was determined by the Nelson method (Nelson, Journal of Biological Chemistry 152 (1944) p.377). This method is used to determine the lactose, but also at the same time any other reducing sugar that may be present, v / ie glucose and galactose, which can be formed when the lactose is hydrolyzed by the bacteria (as is well known, lactose is a disaccharide made from glucose and galactose) .

The direct determination of the proteins contained in the whey after the biuret method is not possible because of the presence of substances that precipitate with the reactants form. Therefore, the procedure is such that 1 - 5 ml of whey is precipitated with trichloroacetic acid, the precipitate once with 5% trichloroacetic acid washes and the protein is then determined using the biuret method.

10 ml of whey were infected with a colony of Enterobacter liquefaciens BCL strain vaccinated. The culture was placed in a sterile 100 ml Erlenmeyer flask and stirred at 30 ° C. Samples taken after certain times were examined for the concentration of bacterial mass. Then were the bacteria are separated off by centrifugation and the filtrates are analyzed.

The following results were obtained:

Growth duration of dry matter bacteria Degradation of the

mg / ml of ornamental sugar

5 hours 1.73 8 hours 3.15 24 hours 6.6 48 hours 4.7

48 80

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Example 2

This example shows the utilization of the reducing Sugar by four different strains of bacteria. The culture conditions are the same as in Example 1 and measurements were taken after 42 hours.

tribe
I. liquefaciens Degradation of the redu-.
ornamental sugar Crock "
of snextrakt
Filtrate Enterobacter
Strain BCL) liguefaciens 76% - - Enterobacter
(Strain 67 I) cloacae 86% 1.3 g / 100 ml Enterobacter 57%

Seratia atypical 3470 69%

The whey had a particularly high lactose content (5.4 g / 100 ml) The dry extract of the whey was 6.1 g / 100 ml.

Example 3

This example and the following show the results, "the with the strain 67 I of Enterobacter liquefaciens.

30 ml of undiluted sterile whey was inoculated with 2 ml of a saturated culture of strain 67 I in whey. the Culture was carried out with stirring at 30 in an Erlenmeyer flask bred.

Growth bacteria breakdown of the breakdown of the redu dry extract

permanent dry matter protein sugar of the filtrate

. mg / ml ■ g / 100 ml

24 Hours. 7th , 5 48 % 1 / 0 - 8th 61 46 Hours. 7th 70 % 8th 86 3 0 9 8 5 3

3.3 1.5

The whey used had a dry extract of 5.8 g / 100 ml and contained 0.36 g / 100 ml protein and 5.2 g / 100 ml lactose.

Example 4

This example used raw whey obtained by simply passing rennet treated milk through a hydrophilic gauze was filtered. 6 liters of this whey were inoculated with 600 ml of a saturated culture of strain 67 I. The fermentation was carried out at 30 ° C in a New Brunswick fermenter of 10 liters with stirring at 400 rpm and good Ventilation carried out; In the course of fermentation, silicone became a defoamer added.

I.
Growth period Bacteria dry matter Degradation of the reducing
Sugar 10 hours 6.9 14% 20 hours 9 27% 26 hours 9.5 • 52% 30 hours 11 57% 43 hours 12th 88%

Acid formation was negligible in this culture; the final pH was 6.2.

The above examples relate to the cleaning of neutral whey, which is produced during rennet coagulation, but the invention can also be applied to the cleaning of sour whey, which by the action of lactic ferments (e.g. the whey produced in the manufacture of soft cheese). In this case the whey is used before inoculation neutralized, preferably by adding ammonia.

The following example describes the cleaning of an acidic whey.

Example 5 '

10 liters of acidic whey, the pH of which was initially 5, was adjusted to pH 7 by adding 70 ml of 14M ammonia .

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The whey was inoculated with 1 liter of a saturated culture of Enterobacter liquefaciens strain 67 I. The fermentation was going on as in Example 4. After fermentation for 12 hours, the medium contained 13 g / l dry bacterial mass and 92% of the reducing substance The sugars were used up. The addition of ammonia, which served as a nitrogen source, was the end of the line 90% of the whey proteins are still present after fermentation.

It should be noted that the cleaning was much faster, namely on the order of 12 hours.

As can be seen from Examples 1 to 4, is after 48 hours most of the lactose and the load album disappeared. It should be noted, however, that bacterial growth generally ceases after 24 hours, when only 50% of the lactose has been consumed, but that the breakdown of the lactose and of the lactalbumin continues - because of this phenomenon, the decomposition of the whey is without prior dilution possible.

The invention thus permits a very satisfactory one Purification of whey with the help of a simple and little Space-consuming facility. The process costs are very low if the fermentation product is obtained Bacterial mass can be used for utilization in animal nutrition. For explanation it should be noted that the Bacterial mass obtained according to Example 5 contained about 50% protein ^ whose composition according to amino acids was as follows:

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Amino acid. Percentage

Lysine. 7.3

Histidine 1.4

Arginine 4.5

Cysteine 1.31

Asparacic acid. + Asparagine 11.92

Threonine 5.57

Serine 5.3

Glutamic acid + glutamine - 12.6

Proline "5.51

Glycine 6.69

Alanine. ■. 9.53

Valine 5.69

Methonine 3.05

Isoleucine 3.95

Leucine 9.48

Tyrosine, 2.19

Phenylalanine 2.68

The table gives the proportion of each of the named amino acids in the hydrolyzate of the bacterial mass in mol percent.

Samples of a culture obtained after inoculation of the sour whey from Example 5 were concentrated in vacuo about 5-fold and in a water bath at 100 ° C. for 20 minutes warmed up. The resulting suspension was orally administered to rats and mice without any evidence acute toxicity.

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Claims (11)

Claims , 1.! A method for the microbiological purification of dairy wastewater, characterized in that this wastewater with the help of at least "one proteolytic, aerobic, non-pathogenic bacterial condition _r which has at least one ß-galactosidase or a lactose oxidase, at a temperature between about 20 and 37 ° C subjected to fermentation and then separates the bacterial mass from the fermentation solution. 2. The method according to claim "^ 1, characterized in that the wastewater is fermented practically undiluted. 3. The method according to claim 1 or 2, characterized in that the bacterial strain used after inoculation an undiluted whey increases the optical density, measured at 600 nm, for at least 24 hours. 4. The method according to any one of claims 1 to "3, characterized in that a bacterial strain of the Enterobactericeae family is used. '> 5. The method according to claim 4, characterized in that a bacterial strain of the genus Enterobacter is used. 6. The method according to claim 4, characterized in that a bacterial strain of the genus Serratia is used. 7. The method according to claim or 6, characterized in that that one or more of the bacterial strains · Enterobacter liquefaciens strain BCL, Enterobacter liquefaciens strain 67 I, Enterobacter cloacae and Serratia atypically 3470 used will. -, · 8. The method according to any one of claims 1-7, characterized in that that the pH of the solution is kept between 6 and 7 by adding a base during fermentation. 309851/0883 9. The method according to any one of claims 1 - 8, characterized in drawing] records that the temperature is kept between 25 and 30 C. 10. The method according to any one of claims 1-9, characterized in that that a sour whey is treated that by Addition of ammonia has been neutralized before fermentation. 11. Use of the according to the method according to any one of the claims 1-10 bacterial mass obtained as fodder. 3098S1 / 0883